1. The Field of the Invention
This invention broadly relates to compositions for souring laundered textile materials and imparting softness thereto. In one of its more specific aspects, the invention is concerned with a method of preparing novel compositions for use in souring and softening laundered textile materials. The invention is further concerned with stock solutions prepared therefrom.
2. The Prior Art
The fibers of textile materials tend to harden and lose their initial soft finish when laundered repeatedly. The dry laundered textile materials also may be harsh and irritating to the skin under some conditions. As a result, softening finishes are applied for the purpose of imparting or resorting the softness properties. In most commercial laundries the softening finish is applied during the souring operation which follows the washing step and washing step and several rinses to remove residual detergent. The final rinse may be the souring operation and the softening finish is conveniently applied at that time.
Quaternized fatty amines are excellent softening agents for textile materials and are widely used for this purpose. However, at best they are only slightly soluble or marginally dispersable in aqueous solutions of inorganic acids of the types most often used in the souring operation and relatively concentrated stable homogeneous liquid compositions or stock solutions cannot be prepared therefrom. It is therefore necessary to make separate additions of the softening agent and the souring agent to the final rinse water in the washer. These separate additions in turn require maintaining separate inventories of the softening agent and the souring agent, separate auxiliary storage facilities therefore while awaiting use, and separate apparatus for making each of the two additions to modern commercial washers.
A suitable stable homogeneous composition containing the proper proportion and concentrations of the softening agent and the souring agent would possess a number of advantages which are attractive from the standpoints of convenience and efficiency. This is especially true when operating modern commercial laundry equipment of the type wherein bulk liquid washing chemicals are stored in auxiliary tanks and are added automatically to the washer through feed conduits at predetermined stages in the washing cycle. Entirely satisfactory compositions having the aforementioned characteristics were not available prior to the present invention due in part to the incompatible nature of the softening agents and the inorganic acid species which are commonly used as souring agents. If available, such compositions would allow the initial construction costs of commercial laundries to be reduced substantially as separate auxiliary apparatus would not be needed for storing and adding each ingredient. Labor and general operating costs would also be reduced substantially as only one addition need be made.